1. Field of the Invention
The present invention relates generally to a refrigerant compressor and, more particularly, relates to a sealing plug device for tightly closing each of inlet and outlet ports of a refrigerant compressor so as to isolate the interior of the compressor from the atmosphere during either the storage of the compressors in a warehouse or the transporting of the compressors from e.g., the warehouse or the manufacturing factory to an automobile assembling site where the compressors are assembled in automobile refrigerating systems, for the purpose of protecting the interior of the compressor against corrosion, dirt and dust.
2. Description of the Related Art
Generally, refrigerant compressors are manufactured and assembled, as an important component of an automobile refrigerating system, in a compressor manufacturing factory. During the final stage of the assembly of respective compressors, each compressor is filled with lubricating oil used for lubricating the interior of the compressor during the operation of the compressor, and also preventing the interior of the compressor from being corroded. For example, as shown in FIG. 6, an inlet port 40a of the refrigerant compressor is formed in an outer portion of the compressor, i.e., a pipe connecting portion 40 to which suction and delivery pipes of a refrigerating system are connected. Therefore, after the filling of the lubricating oil into the interior of the compressor, the inlet port 40a of the compressor is covered with a cap member 50 made of a rubber to seal and isolate the interior of the compressor from the atmosphere. An outlet port (not shown in FIG. 6) of the compressor is also covered by a similar cap member or a plug member. Then, the compressors are transported from the manufacturing and assembling factory to an automobile manufacturing and assembling factory where each of the compressors is assembled in an automobile refrigerating system. Namely, during the assembly of the automobile refrigerating system, the compressor is connected to a condenser and an evaporator of the refrigerating system via the suction and delivery pipes, and pipe joints. Therefore, before assembling the compressor into the refrigerating system, the cap members 50 covering the inlet port and/or the outlet port must be removed so that the suction pipe can be connected to the inlet port 40a via the pipe connector. Similarly, the delivery pipe is connected to the outlet port of the compressor via the pipe connector after the removal of the cap from the outlet port.
FIG. 7 illustrates a different conventional sealing device used for sealing a port of a refrigerating fluid flowing passage, which is disclosed in Japanese Examined Utility Model Publication (Kokoku) No. 4-10478 published on Mar. 16, 1992. In FIG. 7, a sealing member 62 includes a stem portion 62a fitted in a mounting hole of a base plate 63, a sealing portion 62b arranged at an end of the stem portion 62a for closing a port end of the refrigerating fluid flowing passage 61 (a tapered portion of the port of the refrigerating fluid flowing passage) in a sealing condition, and a stop head portion 62c arranged at an opposite end of the stem portion 62a and formed as a large diameter portion capable of preventing the seal member 62 from coming out of the mounting hole of the base plate 63. When the seal member 62 is attached to a portion of a machine body in which the refrigerating fluid flowing passage 61 is formed, the base plate 63 having several through-holes 64 is fixed to the machine body by means of screws 66 threadedly engaged, via the through-holes 64, into screw holes 65 bored in the machine body around the refrigerating fluid flowing passage 61.
Nevertheless, the afore-described cap member 50 of the prior art is securely attached to the suction port 40a of the connecting portion 40 by using only the elasticity of the cap member 50 itself, and therefore, during the transportation of the compressor, the cap member 50 might be loosened due to vibration and shocks, and eventually might come out of the suction port 40a. Further, it often occurs that the compressors must be stocked in a store house before they are assembled in automobile refrigerating systems for a rather long time. Thus, when the compressors are stocked, they are filled with gas to protect the interior of each compressor from dust and dirt, and corrosion. The gas used for this purpose is either helium gas or nitrogen gas which is filled into the interior of the compressors after the respective compressors are evacuated so that the pressure of the gas is higher than the atmospheric pressure. Therefore, the high pressure of the gas may cause the loosening of the cap member 50, and allows the cap member 50 to come out of the suction port 40a.
Further, in the case of the afore-mentioned sealing device of JU-B-4-10478, prevention of the sealing member 62 from coming out of the mounting hole of the base plate 63 relies on only provision of a large-diameter-portion 62c at the end of the stem portion 62a. When the assembly of the sealing member 62 and the base plate 63 should be removed from the machine body 60 by unscrewing the screws 66 at the assembling site, since the shape of the tapered port of the refrigerating fluid passage 61 is very simple, the sealing portion 62b of the sealing member 62 can be easily disengaged from the tapered port. Nevertheless, if the sealing device of JU-B-4-10478 is applied to a refrigerant compressor for sealing an inlet and/or outlet port of a flange joint to which an external pipe is joined, the inlet and outlet ports of the flange joint are formed as bores having a generally complicated shape such as a multi-stage counter bores. Thus, the sealing portion 62b of the sealing member 62 once press-fitted in the inlet and/or outlet port cannot be easily removed. Therefore, the large-diameter portion 62c of the sealing member 62 might be unable to prevent the sealing member 62 from being separated from the base plate 63 when the assembly of the sealing member 62 and the base plate 63 is forcedly pulled away from the inlet and/or outlet port of the flange joint to disengage the sealing portion 62b from the port against a large frictional resistance. Thus, when the sealing device of JU-B-4-10478 is employed for sealing the inlet and/or outlet port of the flange joint of the refrigerant compressor, the diameter of the large-diameter portion 62c must be increased. However, an increase in the diameter of the large-diameter portion 62c of the sealing member 62 will make it difficult or impossible to mount the stem portion 62a of the sealing member 62 in the mounting bore of the base plate 63 even if the large-diameter portion 62c is made of an elastic material so that the portion 62c is elastically shrunk.